The stem has its place of insertion in the region we have just been considering. It is the peduncle of botanists, and in some species it separates from the fruit by a joint--in others it remains attached and separates from the twig, when it is considered a part of the fruit itself, as in the apple and pear. The shape, average length, thickness, and other characters, and especially its mode of attachment to the carpos[46] in the pear, give us some important characters, but these are always somewhat uncertain and variable; hence they are rather relative than positive traits. In apples, stems may be _long_, fig. 47, _short_, fig. 48, or _medium_, according to their projection beyond or concealment within the cavity, being called _medium_ when they simply reach the contour of the outline. They are _slender_, fig. 47; _medium_ or _thick_, _fleshy_, _knobby_ or _clubbed_, fig. 49, according to the amount of their substance and its arrangement. They are _curved_ or _straight_, and _direct_ and _axial_, or _inclined_, according to their direction and relation to the axis of the fruit; and in pears, they often have a peculiarity of the insertion dependent upon their being more or less fleshy; in both plums and pears, this fullness is often arranged in rings surrounding the base of the stem. Some pomologists have taken great pains to measure the length of the stems, which they report in inches and lines. As above stated, this is an uncertain quantity, and therefore of little value, except when taken in relation to other measurements by way of comparison; hence I have preferred to use the above-mentioned terms only in their relation to the axial diameter in describing the apples, unless where their extension is unusual. The variable length of this organ in some varieties is remarkable, and we often find the smallest fruits having the longest stems. When we come to examine the interior portions of a fruit, if it be an apple or pear, we make a vertical section through the axis from basin to cavity. This exposes the internal structure and enables us to judge of the color and other characters of the fleshy pericarp, the length of the axis, the size of the core and carpels, and the number and appearance of the seeds. These characters are possessed of value, and are quite reliable; in many fruits the seeds furnish distinctive indications, and this is particularly the case with the stone fruits, many of which are readily identified by the form and markings of the stones or pits, the _endocarps_ of botany.